Eugenics is the social philosophy that by isolating ‘good genes’, human beings could be improved. Policies first began in the United States in the 1900s, and were implemented to different degrees in countries across Europe. Hitler believed that Nazi Germany would only become strong again by employing tactics of racial hygiene and the elimination of anyone deemed to have weak genetic traits. The quest for the "Ubermensch" and propagation of the Aryan race was a priority of Nazi Germany. Over 400,000 people were forcibly sterilised and a further 275,000 under their “euthanasia” program. The methods used and lengths gone to cover their activities were surreal in their range.